• Advances in concrete construction
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• v.12 no.5
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• pp.391-398
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• 2021

This paper presents an experimental study exploring impact resistant properties of Kagome truss reinforced composite panels. Three types of panels with different materials and reinforcements, i.e., ultra-high-performance mortar, steel fiber, and Kagome truss, were designed and manufactured. High-velocity projectile impact tests were performed to investigate the impact response of panels with dimensions of 200 mm×200 mm×40 mm. The projectile used in the testing was a steel slug with a hemispherical front; the impact energy was 1 557 J. Test results showed that the Kagome truss reinforcement was effective at improving the impact resistance of panels in terms of failure patterns, damaged area, and mass loss. Synergy effects of a combination of Kagome truss and fiber reinforcements for the improvement of impact resistance capacity of ultra-high-performance mortar were also observed.

• Carbon letters
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• v.16 no.2
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• pp.107-115
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• 2015

Impact damages induced by a low-velocity impact load on carbon fiber reinforced polymer (CFRP) composite plates fabricated with various stacking sequences were studied experimentally. The impact responses of the CFRP composite plates were significantly affected by the laminate stacking sequences. Three types of specimens, specifically quasi-isotropic, unidirectional, and cross-ply, were tested by a constant impact carrying the same impact energy level. An impact load of 3.44 kg, corresponding to 23.62 J, was applied to the center of each plate supported at the boundaries. The unidirectional composite plate showed the worst impact resistance and broke completely into two parts; this was followed by the quasi-isotropic lay-up plate that was perforated by the impact. The cross-ply composite plate exhibited the best resistance to the low-velocity impact load; in this case, the impactor bounced back. Impact parameters such as the peak impact force and absorbed energy were evaluated and compared for the impact resistant characterization of the composites made by different stacking sequences.

• Journal of Ocean Engineering and Technology
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• v.9 no.1
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• pp.151-160
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• 1995

The characteristics of low temperature impact toughness and stress corrosion resistance at boiling MgCl$_2$ solution of GTA and SMA weld of duplex stainless steels have been investigated. The impact toughness was highest at the GTAW weld metal and lowest at the SMAW weld, which was almost the same as that of the SMAW heat-affected zone. This was attributable to influence of austenite-ferrite phase balance, and the degree and nature of precipitation that occurred during welding. The SCC resistance of the weldments was slightly higher than that of the base metal, whereas no difference in the SCC resistance was found between two different weldments.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.219-220
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• 2011

The research is for building safety by using fiber reinforced concrete against impact load. The aim of this study is to evaluation of Impact Resistance of mortar by Reinforcement Condition of Aramid Fiber(fiber length, fiber surface treatment, fiber contents, hyrid reinforcement with steel fiber). Thus, the results indicate that it can improve mix condition and impact resistance by fiber surface treatment.

• Journal of the Korea Furniture Society
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• v.24 no.4
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• pp.426-432
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• 2013

Fire resistance and impact sound insulation tests were performed for a floor assembly, of which stiffness was reinforced by shortening the span of floor joists by installing glulam beam additionally in the middle or one thirds of the original span, and which an additional ceiling component was installed apart from floor structure. By applying the isolated ceiling, timber framed floor showed 1 hour of fire resistance even in case that dead load was increased by considering cement mortar layer for radiant floor heating. Insulation performance against light and heavy impact sound was improved significantly by applying the sound absorbing layer of big mass and high elasticity in addition to the stiffness improvement and isolated ceiling.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.37-38
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• 2016

In this study, it evaluate the coarse aggregate mixed effect to impact resistance performance of the fiber reinforced cement-based material. The type of fiber is Hooked-ended steel fiber, and mixed 1vol.% in concrete and cement composites. The impact experiment was conducted by using a spherical shape projectile diameter of 25mm to 170m/s speed and Impact resistance performance was evaluated by measuring the fracture grade, fracture diameter and depth.

• Advanced Composite Materials
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• v.18 no.2
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• pp.121-134
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• 2009

The present study investigated, both experimentally and numerically, the improvement of low-velocity impact damage resistance of carbon fiber reinforced plastic (CFRP) laminates due to through-the-thickness stitching. First, we conducted drop-weight impact tests for stitched and unstitched laminates. The results of damage inspection confirmed that stitching did improve the impact damage resistance, and revealed that the improvement effect became greater as the impact energy increased. Moreover, the stitching affected the through-the-thickness damage distribution. Next, we performed FEM analysis and calculated the energy release rate of the delamination crack using the virtual crack closure technique (VCCT). The numerical results revealed that the stitching affected the through-the-thickness damage distribution because the stitch threads had a marked effect on decreasing both the modes I and II energy release rate around the bottom of the laminate. Comparison of the results for models that contained delaminations of various sizes revealed that the energy release rate became lower as delamination size increased; therefore the stitching improved the impact resistance more effectively when the impact energy was higher.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.3
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• pp.349-355
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• 2020

The purpose of this study is to investigate the effects of types and amounts of fibers on the compressive strength and tensile behavior high strength fiber-reinforced composites under a static load and impact resistance properties of composites under a high-velocity projectile impact load. Three kinds of mixtures were designed and specimens were manufactured. compressive strength, uniaxial tension, and high velocity projectile impact load tests were performed. Test results showed that the amount of fiber has a greater effect on the tensile strength an d tensile strain capacity than the compressive strength, an d the tensile strain capacity was improved by using hybrid fibers. It was also found that the amount of steel fiber had a great influence on the impact resistance capacity of panels. Although the impact resistance capacity of panels could be improved by using hybrid fibers, the difference of impact resistance capacity between specimens was found to be larger than the case of use of single fiber.

• Structural Engineering and Mechanics
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• v.60 no.2
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• pp.211-223
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• 2016

Static loading and fluid impact tests on plates containing mesh reinforcement and polypropylene fibers in ratios of 0 to 3% by volume were performed. The objective was to observe the effect of fluid mass on the total impulse that caused the impact event and the influence of fiber amount on the impact resistance, and to estimate the velocity of fluid that causes scabbing, perforation or total disintegration. The study is the first to express the fluid impact resistance of polypropylene fiber reinforced concrete plates.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.4
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• pp.29-35
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• 2013

The objective of the current study is to evaluate the effects depending on the types of reinforcing fibers being influential in view of mechanical properties and impact resistance of hybrid fiber reinforced concrete (HFRC) for applications to precast concrete structure. Hybrid fibers applied therefor were three types such as PP/MSF (polypropylene fiber+macro synthetic fiber), PVA/MAF (polyvinyl alcohol fiber+MSF) and JUTE/MSF (natural jute fiber+MSF), where the volume fraction of PP, PVA and natural jute was applied with 0.2 %, respectively, while based on 0.05 % volume fraction of MSF. The HFRC was tested for slump, compressive strength, flexural strength and impact resistance. The test result demonstrated that mixture of such hybrid fibers improve compressive strength, flexural strength and impact resistance of concrete. Moreover, it was found that HFRCs to which hydrophilic fibers, i.e. PVA/MSF and JUTE/MSF, were mixed show more improved features that HFRC to which non-hydrophilic fiber, i.e. PP/MSF was mixed. Meanwhile, the finding that PVA/MSF HFRC exhibited better performance than JUTE/MSF HFRC was attributed from the former having higher aspect ratio than that of the latter.